Curated OER
Reflecting Reflections
A triangle rests in quadrant two, from which your class members must draw reflections, both over x=2 and x=-2. This focused exercise strengthens students' skills when it comes to reflection on the coordinate plane.
National Council of Teachers of Mathematics
Bank Shot
Bank on geometry to line up the shot. The resource asks the class to determine the location to bank a cue ball in a game of billiards. Using their knowledge, class members determine where to hit the bumper to make a shot and discuss...
Illustrative Mathematics
Reflections and Isosceles Triangles
Geometers explore symmetries of isosceles triangles by using rigid transformations of the plane. They complete four tasks, including congruence proofs, which illustrate the relationship between congruence and rigid transformations. The...
Illustrative Mathematics
Why Does SSS Work?
While it may seem incredibly obvious to the geometry student that congruent sides make congruent triangles, the proving of this by definition actually takes a bit of work. This exercise steps the class through this kind of proof by...
Curated OER
Why Does SAS Work?
Your geometry learners are guided by questions that help them use the language of reflections to explain the Side-Angle-Side congruence between two triangles in this collaborative task. Given a sample solution, declaring the...
Curated OER
Point Reflection
Use this task as an exit ticket for your eight graders during the geometry unit. All they need to do is identify the coordinates of a point reflected over y=2000.
Curated OER
Symmetries of a Quadrilateral II
Learners investigate the symmetries of a convex quadrilateral in a collaborative activity. Rigid motion and complements are explored as learners analyze different cases of reflections across a line.
Curated OER
Congruent Rectangles
Very simply, geometers examine a pair of rectangles on graph paper and find a translation and rotation to demonstrate their congruence. A couple of questions follow to stimulate critical thinking about other possibilities.
Curated OER
Symmetries of a Quadrilateral I
Learners examine the properties of quadrilaterals from the point of view of rigid motion. Different types of quadrilaterals are characterized by their symmetries, so learners explore the symmetries of a described quadrilateral to...
PBS
Using Symmetry to Create Corporate Logos
Young mathematicians investigate the use of symmetry in graphic design. After first learning about reflection, translational, and rotational symmetry, children use this new knowledge to identify symmetry in letters of the...
Illustrative Mathematics
Similar Triangles
Proving triangles are similar is often an exercise in applying one of the many theorems young geometers memorize, like the AA similarity criteria. But proving that the criteria themselves are valid from basic principles is a great...
National Council of Teachers of Mathematics
The Math Forum: Putt Putt Golf in the Math Classroom
Putt-Putt golf can be a great tool in helping students understand angles and their reflections. Here a teacher demonstrates the "Course," set up in his classroom to assist in explaining to students how to use geometry and angles in...
National Council of Teachers of Mathematics
Nctm: Figure This: Upside Down (Pdf)
What lowercase letters read the same both upside down and right side up? If you have the answer, then you can handle this geometric symmetry math challenge. A one-page activity from the NTCM Math Challenge for Families collection....
Analyze Math
Analyze Math: Reflection Across a Line
Reflect any point, line segment, triangle, or any other figure over one or two lines using this dynamic applet. Points and lines are entered by point-and-click rather than by typing equations or ordered pairs. A very neat exercise to...
Math Is Fun
Math Is Fun: Reflection
Students learn about reflection. An activity, examples, tricks, and a definition are included.
Texas Instruments
Texas Instruments: Connecting Translations, Reflection, and Rotations
In this activity, students will investigate the relationship among the three types of rigid transformations - translations, rotations, and reflections.
Annenberg Foundation
Annenberg Learner: Quilts
Copy a quilt block made of 16 squares. Each block will have one of the four symmetry types: H, M, B, or S and you choose which you think it is.